Epoxy compounds are used in a variety of applications utilizing the ring-opening of an oxirane ring of 1,2-epoxide. In particular, bisphenol A type epoxy resins and novolak type epoxy resins are widely used as materials for semiconductor encapsulants, due to the ease of mass production and low cost, and excellent resistance to heat and water.
Conventionally known epoxy compounds are mainly produced by reacting a compound having a phenolic hydroxyl group with epihalohydrin, and epoxy compounds thus produced contain an organic halogen. Therefore, it is difficult for them to be used as an encapsulant for recent highly integrated semiconductors in terms of reliability. Under such circumstances, considerable efforts have been made to develop methods of producing halogen-free epoxy compounds that do not use epihalohydrin as a raw material, and as such a method, a method of oxidizing the carbon-carbon double bond of an olefin with an oxidizing agent is known.
As the oxidizing agent, a peracid, such as peracetic acid and perbenzoic acid, has been used. However, in such a method, an equivalent amount of acid derived from the oxidizing agent is produced, and thus corrosion, etc., of equipment may occur. In contrast, hydrogen peroxide is inexpensive and non-corrosive, and do not generate byproducts or only water is generated after the reaction. Therefore, hydrogen peroxide is environmentally-friendly and excellent as an oxidizing agent for industrial use.
As one of the methods of producing an epoxy compound from an olefin by using hydrogen peroxide as the oxidizing agent, a method of reacting hydrogen peroxide and an organic nitrile compound with a carbon-carbon double bond in the presence of a basic salt compound, such as a carbonate and a bicarbonate of an alkali metal (see Patent Documents 1-3, and Non-Patent Document 1 below).
Patent Document 1 discloses a method of producing an epoxy compound comprising reacting a polyallylether compound with hydrogen peroxide in the presence of acetonitrile while controlling the pH of the reaction system at 7.5 or higher. However, Patent Document 1 describes controlling the pH of the reaction system and replenishing hydrogen peroxide during the progress of the reaction, but does not describe controlling the concentration of acetonitrile.
Patent Document 2 discloses a method of producing a tricyclopentadiene diepoxide comprising reacting tricyclopentadiene and hydrogen peroxide in the presence of a nitrile compound in an aqueous inorganic acid salt solution. However, Patent Document 2 describes that the pH of the reaction system affects the yield and selectivity of tricyclopentadiene diepoxide, but does not describe controlling the concentrations of hydrogen peroxide and acetonitrile in the reaction system.
Patent Document 3 discloses a method of producing an epoxy compound having an adamantane backbone comprising reacting an allyloxy compound having an adamantane backbone, a nitrile compound and hydrogen peroxide water in the presence of a basic compound. However, Patent Document 3 describes adjusting the pH of the reaction mixture, but does not describe controlling the concentrations of hydrogen peroxide and acetonitrile in the reaction system.
Non-Patent Document 1 discloses a method of producing a cis-cyclooctene oxide comprising reacting cis-cyclooctene, a nitrile compound and hydrogen peroxide water in the presence of potassium carbonate. However, non-Patent Document 1 does not describe in detail controlling the concentration of each component in the reaction system during the progress of the reaction.
Even though the initial charging amount of each component at the beginning of the reaction is described in the above prior art documents, none of the above prior art documents describe controlling the concentration of acetonitrile in the reaction system during the progress of the reaction.